Use your preset shape tool near the bottom on the left side (4th from the bottom)

under the word view at the top is a box with the preset shapes, click it and choose Arrow 14, this comes with PSP, anti alias ck, create as a vector ck, line style - solid, width 3

On the right, Materials, two large color boxes the top box is Foreground the bottom is Background, set the Background to Null using the tiny box under the color on the right, hover and it will say Transparent, set the Background to black.

Now draw out the arrow on your blank image to your liking, if you need to redo, just use edit, undo. right click that layer and convert to raster - using your Pick tool or Arrow, move it to the upper center and if you need to make it wider or taller, this is the time. There is no perfect image for this, just eyeball it.

Using the magic wand and click inside the arrow, Selection at top, Modify, Expand by 3, OK

Click the Flood Fill bucket on the left and go to your Materials to create a gradient.

Click the small black circle under Foreground, the middle selection is Gradient and should change the box colors, now click the box, choose Edit, choose New and give it a name.

click the solid black rectangle and choose a color from your tube now click the small box on the right end of the gradient line - the rectangle turns black again, click it to add another color from your tube. CLOSE, YES

The angle is 45 - Repeat 1 (you can play with the repeat) Style Linear.

OK

Create a new raster below the arrow and click inside the arrow. Selections - Select None.